Hydraulically operated machine



Nov. 13, 1934.

R. R, RABER HYDRAULICALLY OPERATED MACHINE Filed April 18, 1931 2 Sheets-Sheet l Vllll/ /NvEf/Ton B A7. f? PAB?? Nov. 13, 1934. R, RRABER 1,980,356

HYDRAULICALLY OPERATED MACHINE Filed April 18, 1951 2 sheets-sheet 2 INVENTUH 2 PASE? Patented` Nov. 13, 1934 UNITEDVSTATES `HYDBAULICAIIALY OPERATED MACHINE Robert R. Raher, West Hartford, Conn.,v assignor kto Pratt & Whitney Company, Hartford, Conn., a. corporation of New Jersey `Application April 18,1931, seriaiNo. A531,240

4 Claims.

This invention relates to hydraulic operating means for machine tools and in-partieu1ar to means for operating the hydraulic system tol-imit the stroke of the hydraulically moved element;

515i and also to provide means for rendering the hydraulic mechanism again operative vaftereiecti'ng stopping of the hydraulically operated element.

An object of importance of the invention is to positively actuate one of the distributing valves Nici the hydraulic system to stop reciprocation of the hydraulicallyv moved element in a predetermined limiting position.

Another object of the invention is to eiect release of the distributing valve while the hydraulilllically operated member engaged bya table dog is retained in the position to which it is moved thereby, thus permitting normal operation of the table to be resumed,

And nally it is an object of the invention to u Hprovide safety means to limit the table movement by'a part of the hydraulic mechanism so that the table can not be moved beyond safe limits at 'opposite ends of its movement.

' With these and other objects in view, my inaitlventionv .consists in the features of construction and operation set forth in the following specification and illustrated in the accompanying drawings.

In the accompanying drawings annexed herefjto and forming a part of' this specification, I

have shown my` invention embodied in areciprocating table surface grinder but it will be understood that the invention can be otherwise embodied and that the drawings are not to be conjstrued as defining or limiting the scope of the invention, the claims appended to this specification i table travel. By this means the safety stop may being relied upon for that purpose.r In the drawings:

Figure l1 is a front elevation of a grinding mar ichine to which the present invention is shown applied.

Fig. 2 is a sectional View of one of the valves of the hydraulic system showing its relation to a plunger forming a part of this invention. y

Fig. 3 is a front elevation of the valve operating member showing one of the actuating dogs on the hydraulically reciprocated table and its connections to a valve of the hydraulic system.

Fig. 4 is a side elevation of the mechanism shown in Fig.'3, showing also thetable reversing rocker. y n

Fig. 5 is a detail view of the normal means for controlling the operation of the valve shown in of a vvset of table reversing dogs and the controller lever operated thereby.

Fig. 7 is a vertical sectional view taken on the plane of line 7 7, and

Fig. 8 is 'a similar View taken on the plane of sbl line 8 8.

In the above mentioned drawings I have shown but one embodiment of the invention which is now deemed preferable, but it is to be understood that changes and modications may be made es within the scope of the appended claims Without departing from the spirit of the invention. f

In the operation of hydraulic actuated machine tools it is desirable to provide a positive vsafety K device rendering the hydraulic system inoperative as soon as the table or other part operated hydraulically reaches a critical or limiting position to prevent overrunning this safe limit. For this purpose the table or member operated hydraulically is provided with dogs or cams so positioned f that they may vact upon and render the hydraulic system inoperative when the element reaches ay critical position in each direction of travel, Engaging these cams is a mechanically operated device acting upon a valve in lthe hydraulic system to positively move the valve to a neutral or inoperative position.- The invention also comprehends a releasable connection in the device acting upon the valve so that the valve may be returned to its operative position while the table remains in its limited position and the'mechanically operated device remains in its actuated position. The invention also comprehends setting the table reversing means in position to reverse the table simultaneously with operation of the safety stopping means at one end of the be employed to rapidly bring the table to Ia stop in an extreme position for loading and unloading the table or other purpose, after which operation may be resumed without delay.

13 onvwhich may be secured work pieces such as v105 shown at W to be ground. This table, adjacent itsv ends, is provided with dogs indicated generally at 1 4, the position of which is determined by the maximum stroke for which the table may be designed. These dogs `14 are supplementary to 11o the adjustable dogs 48, presently to be more fully described, adjustably positioned for any given or desired stroke. The dogs 14 are designed to prevent any movement of the table beyond safe limits in either direction. These dogs 14 therefore may be fixed permanently in position upon the table 13 in positions to engage the upper end of a vertically movableybar or rod 19, 'presently to be morev yfully described when the table reaches the end of its travel.

'Ihe dogs 14 are provided with inclined cam surfaces 15 engaged by a rearwardly extending lug 19L (Fig. 4) upon the upper e'nd of the verti.

cally movable bar 19. The vcam surfaces are such that the rod 19, as the table 13. moves ,in p either direction so that a surface 15 engages the lug 19a, is first forced to move to an extreme upward position. Thereafter any continued U movement of thetable 13 in the same directionI forces the lug 19a and its rod 19 downward. An'

oppositely inclined surface f16 onjtheY cam;y is

provided to effect this downward movement., of

ther rod-19and lug 4119i. k Adownwardly inclined surface 18 on a cam member 17 positivelyforces the rod\1 9downwardby'engagement with a roller 19h on the rod 19.r When thus moved downwardA the rod .19 is maintained in its downward; position -by engagement of its `roller 19h with thel horizontalsurface 1 8* 1 ofthe cam member 17.

.39g This surface 18a extends parallelly to thev direc# tion of movement of the table and maintains the roller 19b and rod `19 against any upward,v

movement. The vertically movablerod 19 is supported ad- 355; jacent its upper end by being slidably mounted within a Suite101@ bracket zovattechee rigidiy mf position upon a portion ofthe base 10, Thisv lodA 19 is provided -with a pivotally mounted handle 22 spring pressed in a direction as shown in Fig.

40,1g4 to maintain the handle 22 in. position to hold` down ra plunger 21 presently lto be described.`

Upon being osciuated upon itspivot 23 to the position 'shown in dot-and-dashl lines in Fig. ;4 the handle` 22 allows vthe plungerf21 to move ver- @y tically upward. l Preferably and-as indicated inl -Figs.; Bland 4jthe lowerendof the bar or rod 19k has aV recess extending axially from its lower end so that the plunger 21 extends freely within the recess within the rodv19. y The lupper end ofV thel 59, plunger 21, with the Ahandle member 22.in the` 7" position` shown in full lines, engagesl a notchedv portionhthereof southat so long as the handle member 22 remains inv this position the plunger 21v must move -down with downward .move--r ment of the rod. As soon, however, as the handle 22 is moved tothe position shown in dot-and-das'h Q lines, the plunger 21 may move upward within therod or bar 19 as bymeans of'a spring presenti;l ly to be referredto. Thejhandle lmember"2l2 is- Gdgpivoted to then bar l.19', atdits upper*` end, as indie.

cated at 23, and its verticallydisposed 'portion may enter an elongated slot formed in the bar 19. The handle `.22 will therefore retain its erigagementwith the upper end of plunger 21', and

.will be normally retained4 in engaging: position by its spring. f r

This manger 21 is sndamy'nfwuntea in affixed,

HousingV member 25 Iadjacent the. hydraulic conf trol mechanism and is providedalong one sidev Wwlth'a number .of rack teeth. Thesefrackte/eth are adapted to engage a pinion 27 upona' hori-y zontally disposed shaft 26 rotatably mounted upon L affixed axis within the fixed member 25. 'The fixed Vmember 25 vmay be attachedby any con- -fvenient lmeans'. (not shownlto a portionofthe a horizontally disposed plunger 30 slidably mount- .ed for axial movement within the fixed support 25.` One of the ends of this horizontally movable plunger BUeXtends-outside the fixed member 25 v"retaining member 25.

andabuts against the end face of a control valve 31o`f thehydraulic system. Movement of plunger 30-to the. leftjwill .therefore move valve 31. Movement'of the horizontal plunger 30 in the one dl- 'relctio'neis limitedby-a suitable plug 31a closing one en d of the opening for the plunger 30 in the vThe valve 3.1, as shown in Figs, 2j and 35 isprovided with a spring 39 pressing againstone end;` so mounted that its effect is to normally force the plunger 30 in fa .direction away from the valve/31.V Preferablyand as shown, the. spring 39 maybe housedjwithin a recess provided in the lplunger 30, @Degene bearing.' against, a Din 40 ,extending through theplnngerf30- lThe opposite end ofthe spring 39 -tal;es up against av suitable abutment 40a' within thelhousing 25,v the plunger having anV elongated slot togpermit free movementthereof.

In the position of the valve 31 shown in Fig. 2, ports are opentoadmit fluid under pressure from the pressuresupplyconduit 33, past the reduced or ynecked, portion 32 of the va1ve31 into a con-y duit34 leading'to a reversing or distributing valve' controlling the v.admission of fluid vto Aopposite ends yof 4a cylinder'to actuatethetable 13. This is the .position ofthe valve 31 assumed during normal operation ofthe grindingy machine,` the 115 fluid after entering the conduit 34 beingdistrib-- utedby any suitable form of hydraulic-mechanis'm` (not shown). Conduits 3.6 are provided onopposite sides ofthe above described ports to dis-V4 charg'eany fluid leaking past portionsr of the valve 3 1'. ,Assoonas the roller 190-up'0r1t11e` .upper-end off the rod 119,'engages, one of the cam surfaces 18 and is moved'downwardQthe horizontal plunger- 30 ismo'ved, to the left and forces the. valve. 31* toapOsition considerably to the'left 'of the-:posi-V tion shownfullflines. /Withthe valve'31 in-. this left-hand position, ,the pressure supply con` 4 duitl33 is openkdirectly to a return conduit 35 by thenecled portion` 32'of'the`valve 31 so thatthe fluid vinstead.o'fgoiifigto the cylinder for effectingy v30 reciproca'tory movements ofthe table ,13 is4 bypassedA lto -suitable. exhaust 'passage Awithout an'yv 1- eifect upon theA 'table' movement..

, Therad 19 above referred toisnormallyheld in'. zl'i'perative `relation to `,the plunger `*3( 1 as'` shown. 135 in full'lines in Fig. 2 so that' the vertical plunger 211 w-henthe-rod19 is, engaged. by; one ofthe cam surf'a'.ces'lv will move 'the plunger 30 to its'extremer left positionand move the ,valve'l toward theleftas abovedescribed. Movements ofvr the '140 upper` end ofthe rod'19 by engagement of the lugv19e'fwithvthecam surfaces'l `and 16 vtakes' placeI only'fwhe'n'the table -13 :approaches its extremelimitsof travel.v After 'the table"13 has been broughtto rest afterdepressingv of. the rod 19,- 145 means must be provided to release the vvalve 31 so thatnormal operation may be. resumed. For" this purpose ltheY handle 22111211.37 v1013 manually moved' to its' dot-and-'dash position. vWith, the handle 22withdrawn to the dot-and-dashor in# 150I loo operative position shown in Fig. 4, with'the rod 19 vin its `lower position-the plunger 21 is releasedfrom its engagement with the rod 19 at 'the notched kportion of the handle land therefore releasing the horizontal plungerBO so that thevalve 31 is free-to be moved to its position shown in Fig. 2 by spring 39. .Should `the table 13 approach its limit position while the handle 22 is inthe position .shown in dot-and-dash lines in which the vertical plunger 21 ris disengaged from the handle .22 and the rrod 19, the following 'takes place. The lug 19a first engages :the inclined surface 15 so that continuedmovement of the table 13 first raises the rod 19 toits uppermost position. In this elevated position the rod 19 is in position to engage the handle member 22 over the upper end of the plunger 21, thus rendering the plunger 21 operable by the rod 19. Further movement of the table 13 causes the roller 19b to engage the oppositely inclined surface 18 on the cam or dog 14 so that the rod 19 and plunger 21 are moved downward in the manner above described.

In Fig. 5 the operating connections for normally controlling the valve 31 are shown. The lefthand end of the valve 31 has a circumferential recess 38 engaging an arm of a bell crank lever 41 pivotally mounted at 42 within the base 10. The other arm of bell crank lever 41 is pivoted to a reach arm 44. To retain the bell crank lever 41 in any of its oscillated positions and therefore retain the valve 31 in any of its operative positions a detent 43 is provided. Preferably and as shown, the detent 43 is spring pressed toward the arm of lever 41 and its forward end enters one of Ithe angular notches.

At the upper end of the reach arm 44 is connected a handle 45 pivoted at 46 in the base. By oscillatory movement of handle 45 movements of the valve 31 may be obtained to start and stop operation of the machine.

In Figs. 1 and 6 are shown the table reversing dogs adjustable along the length of the table 13 to vary its operative stroke. These dogs 48 will be suitably spaced apart for varying strokes of the table and will be positioned in opposed relation to each other. These dogs are shown generally at 48 and are slidably mounted upon suitable ways formed upon the table 13. By means of catch levers 49 on the dogs 48 engaging teeth "of a rack 50 secured to the table 13 the position of the dogs 48 may be easily adjusted. Fixed to a shaft 51 disposed horizontally in the base so that they may oscillate said shaft are table reversing or controller arms 52 and 53 adapted to contact respectively with the dogs 48. Preferably each of these arms 52 and 53 is provided with a roller 54 for engaging one or the other of the cam surfaces of dogs 48. Also on shaft 51 is a controller lever 55 adapted for manual oscillation.

AOperation of this lever 55 either by hand or by the cam surfaces on dogs 48 acting on the arms 52 and 53 effects reversal of movement of the table by action of one of the hydraulic distributing valves. As the operation of the hydraulic mechanism by oscillation of this lever 55 forms no part of this invention and may be of usual or standard construction, the mechanism will not require description and is not shown. In the position shown in Fig. 6 the table is traveling in the di- ;rection of the arrow and is on the point of being reversed by engagement with the roller 54 on arm 52 by surface 56 of dog 48.

Associated with the dog 14 adjacent one end of the table 13 operating the rod 19 is a dog 57 secured in fixed position upon the table 13 as shown most lclearly in Fig.` 6. 'On this dog 57 is surface 58 engaged by the roller 54 Vupon arm 52. By means of this dog 57 the hydraulic mechanism is reversed by oscillation of the table reversing lever` 55 simultaneously withengagement of the rod 19 with the cam surfaces of the dog 14 adjacent cam 57. The hydraulic mechanism by operation of lever 55 is therefore set for reverse travel of the table 13 'when the rod 19 acts upon the Valve 31. As soon therefore as the starting lever 45 is operated to again start the table, the table Vstarts upon its return stroke. 1

By reference to Fig; 4 it will 4be seen that the cam surfaces of the two opposed dogs 48 are .in adjacent planes and the rollers 54 engaging them are out of alignment with each other and disposed for operative engagement respectively with said surfaces. The dog 57 has its roller engaging surface in alignment with the outermost dog 48. By this arrangement the reversing lever 55 carrying the arms 52 and 53 is free to be oscillated by this cam surface.

The reversing lever 55 and the arms 52 and 53 are movable axially a slight distance on the shaft 51, as indicated in dotted lines in Fig. 4. This is provided for the purpose of moving the rollers 54 out of engagement with the surfaces of dogs 48 so that the rollers 54 can pass their respective surfaces on the dogs 48 when the table is to be brought to its extreme end position.

What I claim is: l

1. A stop mechanism for a hydraulically actuated member including in combination, a cam carried by said actuated member, a rod mounted upon the base on which said member is actuated and one end of which intercepts the path of movement of said cam, said rod being moved in opposite directions by engagement with said cam, means to effect engagement of said rod with said cam in any position of said rod, a valve in the hydraulic system for controlling the supply of fluid for operating said member, a plunger for moving said valve in one direction when said rod is moved downward, and means to disengage said rod from operative connection with said plunger permitting return movement of said valve while said rod is retained by said cam in its downward position.

2. A stop mechanism in combination with a hydraulically actuated member including in combination, a cam carried by said actuated member, a rod mounted upon the base on which the member is actuated and one end of which intercepts the path of movement of said cam, said rod being moved in opposite directions by engagement with said cam, means to effect engagement of said rod with said cam in any position of said rod, a valve in the hydraulic system for controlling the supply of nuid for operating said member, said Valve being moved in one direction by downward movement of said rod, and being so held by said rod, said valve being movable in either direction while said rod is in its upper position, and means to render the rod inoperative to hold said valve while said rod is held down by said cam whereby return movement of said valve is permitted.

3. A stop mechanism in combination with a hydraulically actuated member including in combination, a cam carried by said member, a rod mounted upon the base on which said member is actuated and said rod movable in opposite directions by engagement with said cam upon movement of the hydraulically actuated member to a predetermined position, a valve in the hydraulic system for controlling the supply of fluid for actuating said member, said valve being actuated by movement of said rod in one direction, said rod holding the valve in its actuated position to stop movement of the hydraulically actuated member, said valve being movable in either direction while said rod is at the end of its return movement in the opposite direction, means to cause said rod to actuate said valve as the member approaches the end of its movement, and means to release said valve from its rod actuated position while said hydraulically actuated mem-y ber is in said predetermined position.

4. A stop mechanism for a hydraulically actuated member including in combination, spaced cams carried by said member, a', 'rod m'ounted upon the base on which vsaid member is actuated and movable axially by engagement with either of said cams, a valve in the hydraulic system for controlling the supply of uid for operating said member, connecting means mounted on and movable by downward movement of said rod Ato force said valve ltoward a neutral position,'-means on said rod to disconnect said last mentioned means whereby said valve may be released for normal operation with the rod in its downward position,l and means to re-engage said connecting means upon upward movement of lsaid rod. f

ROBERT R. RABER. 

